GPIO MIOs from linux kernel

Question

Hi,

I would like to know how to access to GPIOs MIO from Linux kernel.

I'm not completely sure how to do that.

I can see in my picoZed in the /sys/class/gpio the folder gpiochip0 and inside this folder the file ngpio with a value of 64. But I not completely sure if this is the MIO GPIOs, because the MIO are 54 GPIOS:

MIO0 pins 0 to 15 -> connected to a 3.3Volts bank

MIO1 pins 16 to 53 -> connected to 1.8 Volts bank

Am I right or wrong?

Best regards.

oscargomezf · Accepted Answer

Hi,

I was reading the /proc/device-tree/amba/gpio@e000a000 with a width of 64 bits. And I've tried to configure de PS_MIO51 as an input to check the PS_PB button in the PicoZed FMC Carrier V2:

$ echo 51 > export

$ echo in > 51/direction

$ cat 51/value

And when I pressed that button I've got and 1 and when the button is released I've got a 0, So it's working fine. But If I only have 54 GPIOS (From 0 to 53) Whats happen with the GPIOS from 54 to 63? I think It has to be a width of width instead of 54 because it has to be a power of 2 and If you try to access to the pins from 54 to 63 nothing happens, but I'm not completely sure.

Best regards.